Melt polycarbonate catalyst systems
US6376640B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 12, 2001 |
| Grant date | Apr 23, 2002 |
| Priority date | — |
| Expiry date | Jan 12, 2021 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G64/307
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
This invention provides a method for preparing polycarbonates, which utilizes polycondensation catalysts of the formula Cs+An−, wherein An− represents anions such as CH3SO3−, NH2SO3−, C2H2O4−, BF4−, B(C6H5CH3)4−, and CH3C6H4SO3−. We have found that this new class of catalysts provides excellent polymerization rates for the preparation of Bisphenol A polycarbonate from the melt polymerization of diphenyl carbonate and Bisphenol A. Moreover, the catalysts of the invention were found to be very selective in substantially reducing the level of branching side reaction, i.e., formation of Fries product, normally associated with the melt polycarbonate process.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.